Fuel Injectors

[Parker]

I was wondering if there is a need for smaller injectors than would come stock on a 600cc bike or not. by our calculations, BSFC, airflow and such, the pulsewidths down low come awfully close to the response time we were told for the injectors.

[Parker]

I was wondering if there is a need for smaller injectors than would come stock on a 600cc bike or not. by our calculations, BSFC, airflow and such, the pulsewidths down low come awfully close to the response time we were told for the injectors.

[Erich Ohlde]

We run and F4i with AEM ECU and stock injectors and have since 04. We've never had a problem with the low end performance. gotta remember the stock setup is going to use low pulsewidths just like your setup at low revs

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Parker:
I was wondering if there is a need for smaller injectors than would come stock on a 600cc bike or not. by our calculations, BSFC, airflow and such, the pulsewidths down low come awfully close to the response time we were told for the injectors. </div></BLOCKQUOTE>
Normally the pulsewidth generated by the ECU will consist of a 'response' portion (to open the injectors) and a 'delivery' portion (to deliver the required pulsewidth of fuel). The terminology varies from manufacturer to manufacturer, but typically the calculation is handled internally (and often depends on battery voltage also). Often the delivery during the opening time is considered to be half.
So, if you ask for 1ms and the injector response is 1ms also, the ECU might generate a 1.5ms pulse.
Regards, Ian

[Parker]

Thanks for that Ian. We have never even come close to making that assumption, when it seems like it should have been there and looked for the whole time.

[murpia]

Also explained here:
http://www.megamanual.com/v22manual/mtune.htm#constants
That whole site is a goldmine of info, too:
http://www.megasquirt.info/
http://www.megamanual.com/
Regards, Ian

[B Lewis @ PE Engine Management]

Parker,

I think that most of the teams tend to use the stock injectors and they perform very well.